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Finding the Fourth Proportional to 1,290.29, 1,780.19 and 786.25

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Solution

The fourth proportional to 1,290.29, 1,780.19 and 786.25 is: 1,084.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,290.29 : 1,780.19 = 786.25 : x
  2. Step 2: Convert to fraction form
    1,290.29/1,780.19 = 786.25/x
  3. Step 3: Cross multiply
    1,290.29x = 1,780.19 × 786.25
  4. Step 4: Simplify right side
    1,290.29x = 1,399,665.49
  5. Step 5: Solve for x
    x = 1,399,665.49/1,290.29
  6. Step 6: Final answer
    x = 1,084.77

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Half scale
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Double scale
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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.